The present invention relates to a method of adhering polishing pads of a polishing apparatus, which is capable of simultaneously polishing both faces of a work piece, and a suitable jig for the method.
Various types of polishing apparatuses, each of which is capable of simultaneously polishing both faces of a work piece, e.g., wafer, are known. For example, Japanese Patent Gazette No. 2000-42912 discloses a conventional polishing apparatus, in which a carrier holding wafers is circularly moved without rotating about its own axis between a lower polishing plate and an upper polishing plate, which can be independently rotated, so as to simultaneously polish the both faces of the wafers.
The conventional polishing apparatus disclosed in the Japanese patent gazette will be explained. FIG. 7 is an exploded perspective view of the polishing apparatus; FIG. 8 is a sectional view of the polishing apparatus shown in FIG. 7.
The polishing apparatus 100 comprises: a carrier 12 formed into a thin circular disk having through-holes 12a; an upper polishing plate 14 having a polishing face 14a; a lower polishing plate 16 having a polishing face 16a and being relatively moved toward and away from the upper polishing plate 14; a carrier orbiting unit circularly moving the carrier 12, without rotating about its own axis, together with wafers 10 between the lower and the upper polishing plates 14 and 16; a slurry feeding unit 85 pressurizing and feeding slurry to the polishing faces 14a and 16a contacting the wafers 10 via slurry feeding holes (not shown) of the upper polishing plate 14 and/or the lower polishing plate 16.
In polishing apparatuses, polishing pads, which are adhered on polishing faces of polishing plates, are gradually abraded with polishing wafers. Therefore, polishing pads must be exchanged periodically. In the above described conventional polishing apparatus capable of simultaneously polishing both faces of the wafers, the polishing pads adhered on the upper polishing plate and the lower polishing plate must be exchanged. However, the polishing pad adhered on the upper polishing plate must be exchanged in an uneasy posture, so that it takes a long time to exchange the polishing pads.
In the polishing apparatus, the polishing faces, which will contact the wafers, must be highly precisely flat, so the polishing pads must be securely closely adhered on the lower polishing plate and the upper polishing plate. The polishing pad can be easily adhered on the lower polishing plate. However, as described above, the polishing pad adhered on the upper polishing plate is exchanged in the uneasy posture, so it is difficult to closely adhere the polishing pad on the polishing face of the upper polishing plate. If the uneven polishing pads contact the wafers, the wafers cannot be polished uniformly. Production yield must be lowered.